Call it the Greenland New Deal. President Trump's interest in America purchasing the vast territory known as Greenland is being met with laughter and derision in Denmark, its ostensible owner. "It has to be an April Fool's joke," a former premier, Lars Lokke Rasmussen, twittered. Martin Lidegaard, of the Danish Social Liberal Party, is calling it "a grotesque proposal." If it's true, a spokesman for the Danish People's Party reckons, it's "final proof" that Mr. Trump "has go...